Machine for clamping and drying hides, particularly bovine, sheep and goat skins

ABSTRACT

A machine for clamping and drying hides comprising a drying oven and guide rails for the frames carrying and stretching out the skins. The guide rails comprise an external section located above the drying oven and other sections located inside the oven. There are provided kinematic assemblies arranged to transfer the frames from one to the other of said sections. Means are also provided for varying the size of the frames so as to stretch and relax the skins supported thereon. The skins are fixed on the frames by means of automatically actuated grips.

United States Patent Polvara Nov. 26, 1974 MACHINE FOR CLAMPING AND DRYING 2,488,907 11/1949 Griffin et al. 69/1 HIDES PARTICULARLY BOVINE, SHEEP 2,834,147 5/1958 Durkee 69/19.3 3,075,297 1/1963 Argabrite et al 69/1 AND GOAT SKINS Diego Polvara, Viale Lombardia, Brugherio, Italy 20047 Filed: Feb. 12, 1973 Appl. No.: 331,415

Inventor:

Foreign Application Priority Data Feb. 17, 1972 Italy 020692/72 References Cited UNITED STATES PATENTS 8/1914 Noblett 69/19.3 3/1927 Kornitz 69/l9.3

Primary ExaminerAlfred R. Guest Attorney, Agent, or Firm-Dr. G. Modiano; Dr. A. Josif [5 7 ABSTRACT A machine for clamping and drying hides comprising a drying oven and guide rails for the frames carrying and stretching out the skins.

9 Claims, 6 Drawing Figures This invention relates to a machine for clamping, stretching and drying hides, particularly bovine, sheep and goat skins.

BACKGROUND OF THE INVENTION Machines of this type essentially comprise drying vens of various types and forms, into which the frames on which the skins to be dried are stretched out are inserted in a vertical position. Both the insertion and extraction of frames, which .can slide along suitable guides, and the stretching of the skins on the frames when they have been fixed are even now carried out maually. The typical cycle of operations comprises firstly the extraction from one end of the oven of a frame on which a dried skin is stretched out. The frame, in the vertical position, is caused to slide along suitable rails extending to the outside manually by two operators, who then rotate the frame about appropriate hinges so as to bring it into a horizontal position and then proceed to the opening of the grips which are fixed to the frame and hold the skin stretched out.

When these operations have been carried out, a new skin is arranged on the frame and the grips are manually closed on to it. Then the skin is stretched out by manually acting on the grips which clamp it, and then fixing these latter to the frame by appropriate engagement members, the position of which may be varied. The frame with the skin stretched out on it is then again rotated into the vertical position and reinserted in the oven for a new drying cycle.

It is evident at this point that the heavy incidence of manual labour on the treatment cycle leads to grave disadvantages.

The processing stages outside the oven are slow and laborious, and this represents a stage in the general treatment cycle for the skins which slows down the entire process. Furthermore it is difficult, even for very able workers, to stretch out all the skins to the required degree in a uniform manner, so that the quality of the product obtained suffers.

SUMMARY OF THE INVENTION The main object of this invention is to eliminate all the aforementioned disadvantages by providing a type of machine for clamping and drying hides which can carry out a completely automatic processing cycle from the gripping and stretching stage to the drying stage and the removal from the frames, leading to a considerable saving of time and removing the processing cycle from the personal variable abilities and efficiency of the workers concerned.

This and further objects which will be more evidnet hereinafter are attained by a machine for clamping and drying hides, comprising a drying oven and guide rails for a plurality of frames for supporting and stretching out skins, characterised in that the external structure of said oven defines with its upper part a working surface on which a section of said guide rails is fixed, another section being located inside said oven and extending substantially parallel to the said section fixed on said working surface, there being located at the ends of said sections of guide rails kinematic assemblies arranged to transfer a frame from one to the other of said sections,

means being provided below said working surface for increasing or decreasing the size of said frames so as to stretch and relax skins supported on said frames, and means being also provided for automatically opening grips connected to said frames for gripping said skins.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the invention will be more evident from the detailed description of a preferred but not exclusive embodiment of a machine for clamping and drying hides, illustrated by way of nonlimiting example in the accompanying drawings in which:

FIG. 1 is a diagrammatic section through a longitudinal vertical plane of the machine according to the invention;

FIG. 2 is a plan view of the machine of FIG. 1; FIG. 3 is a section on the line Ill-III of FIG. 1; FIG. 4 shows a frame on which a skin is stretched out;

FIG. 5 is a detailed view of a grip for gripping and stretching out a skin;

FIG. 6 is a detail of the frame of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the stated figures, the machine according to the invention comprises a supporting structure 1 for a drying oven 2' which extends horizontally.

Above the oven 2, the side walls of which are visible in FIG. 2, is fixed a section of rails 3, which extend along the outside of the oven 2 for a distance slightly less than its length. Inside the oven2 are two sections of rails 4 and 5 parallel one to the other. The section 4, placed underneath, extends over the entire length of the oven 2, whereas the section 5, placed upward, is interrupted prior to one end.

Frames 6 are coupled to the rails and comprise two axles 7 joined together over a section by a laminar structure 8 which comprises a plurality of holes 9.

The free section of the axles 7 serves as a sliding guide for sleeves 10 joined together by a perforated laminar structure ll entirely similar to the structure 8. More precisely, a tooth 13 is fixed to each of the axles 7 by means of a collar 12, and is arranged to engage with a ratch 14 formed on an arm .15 rotatably pivoted to the sleeve 10. The arm 15 comprises at its free end a head 16 arranged to act against a fixed stop or releasing cam means 17 so as to disengage the tooth 13 from the ratch 14. Wheels 18 arranged to run on the rails 3, 4 and 5 are rotatably pivoted on the ends of the axles 7. Kinematic assemblies indicated overall by the reference numerals 19 and 20 are fixed at the two opposite ends of the machine for transferring the frames 6 from the rails 3 to the rails 4 and 5, and from the rails 4 and 5 to the rails 3 respectively. More precisely, the assembly 19 comprises a motor 21 which drives chains 22 wound around wheels 23. Dogs 24 arranged for grasping a frame 6 are fixed to the chains 22. A suitable switch, 21a of known type and donsequently only schematically indicated, reverses the direction of rotation of the motor 21 at the appropriate time. The assembly 20 comprises a motor 25 which drives chains 26 wound around wheels 27. To each of the chains 26 is fixed a dog 28 and a pawl 29 for moving a frame 6 in both directions along a guide formed from inclined rails 30. A suitable switch, a of known type and consequently only schematically shown, reverses the direction of rotation of the motor 25 at the appropriate time. At the ends of the rails 3 there are unidirectional switch points 31 and 32, i.e., operable only in one direction, as indicated by the arrows 33 and 34 respectively. Below the rails 3 and laterally at a distance therefrom there are jacks 35 and 36 provided with forks 37 and 38, arranged to engage, when in extended position, with the mobile part 11 of the overlying frames 6 for moving the part 11 towards or away from the fixed part 8 respectively by making it slide on the axles 7. When the forks are in retracted position they are clear of the advancing frames. The jacks 35 and 36 are controlled by not shown limit switches of known type.

For fixing a skin 39 to any frame 6, grips are used of the type shown in FIG. 5 and indicated overall by the reference numeral 40. The grip 40, which is provided with a pin 40a for fixing it to one of the holes 9 of the structure 8 or 11, essentially consists of a fixed part 41 which carries a jaw with two beaks 42 and 43 and a holding ring 44.

Rotatably pivoted to the end of the beak 43 is a lever 45 shown with differently dotted lines in the two extreme positions which it can assure. The lever 45 comprises a crest 46 facing towards the beak 42. The lever 45 is urged against the beak 42 by a spring 47 and comprises at its free end a pin 48 arranged to engage with a ratchet 49, pivoted at'50 to the fixed part 41 of the grip 40, for locking the lever 45 in the open position. The ratchet 49 is held erected position by a spring 51, which urges it against a stop 52 with which it engages by means of a tooth 53. Finally a wheel 54 is pivoted on the free end of the lever 45 for engagement with a horizontal flat plate 55 (see FIG. 1) situated above the plane of the rails 3 and movable hydraulically in a vertical direction.

The operation of the machine according to the invention is as follows. It is assumed that the movement of the frames 6 on the various sections of rail is caused exclusively by the motors 2] and 25 which, under the control of a timer, each push one frame at a time in a stepwise movement with halt intervals, the remaining plurality of frames 6 being moved by the frames directly operated by the motors, by transitive action.

For ease of description, three positions or stations which are attained by any of the general frames on the rails 3 are indicated in FIGS. 1 and 2 by the reference letters A, B and C.

A frame 6, free from skins but with the various grips 40 fixed and kept open by the engagement of the ratchet 49 with the pin 48, arrives at the station B in the manner which will be hereinafter described. The frame 6 arrives at said station B in its retracted arrangement, i.e., with the mobile part 11 close to the fixed part 8. In this station the two operators responsible for working the machine deposit a skin 39 on the frame 6, then manually clamp the skin 39 with an adequate number of grips 40 which are already on the frame in the open position as stated. The only operation to carry out is that of moving the ratchet 49 so as to free the lever 45, which snaps into a position which clamps the skin between the crest 46 and beak 42 of the grip 40. Then each grip is arranged in one of the holes 9 by the pin 40a.

. As the frame 6 moves further forward, its right axle lowers by gravity and brought in engagement with the dogs 24 of the chains 22, whereas its left axle pushes on the switch points 33, which allow it to fall on to the underlying rails 5. Under the action of limit switches 21a. The motor 21 automatically drives the chain 22 so that the frame 6, by pivoting about its wheels on the rails 5, engages with the rails 4 by way of the axle 7 supported by the dogs 24 which are released. The frame has thus entered the drying oven 2 and is contained there in an inclined position in order to save vertical space.

As visible from drawing (FIG. 1) the dogs 24 have a hook like formation which so engage the axle 7 that the axle is supported and at the same time pushed leftwards in the drawing during the descending movement of the dogs 4, or the counterclockwise movement of chain 22.

Each frame 6 which enters the oven 2 pushes ahead the frame which is in front of it. In this manner each frame 6 travels through the entire oven 2 in a determined time from right to left, and the skin supported on it is dried as required. It should be noted that when the general frame 6 has entered the overn 2, through the action of limit switch 21a the motor 21 automatically reverses its motion and brings the dogs 24 into the upper position for receiving a new frame from the rails When the frame 6 collides against the guide 30, that axle of it which is in the higher position becomes supported on the dogs 28. At this point upon actuation of limit switch 250 the motor 25 drives the chains 26, so that the frame 6 is caused to rise along the guide 30. The frame crosses the switch points 32 and when said points are crossed also by the axle in the lower position, the motor 25 reverses the direction of motion of the chains 26 so that the pushers 29 can push the switch frame 6 downwards. The points 32, which are now engaged from the side on which they do not open, deviate the frame on to the rails 3. The frame is thus pushed by the rollers 29 to the station A.

It is evident that the limit switches which are known in the art are actuated in known way by elements also rigid with the chains 22 and 26 which elements may be constiuted themselves by the dogs 24 and 29. Before the frame stops in the station A, the stops 17, arranged in the reach of the station A under the guide rails, act on the heads 16 of the arms 15 so as to disengage the racks 14 from the teeth 13.

The stops 17 are shown in FIG. 6 in cross-section. It will be understood from the describe function which the stops have to perform that they are constructed of an upwardly inclined bar extending transverse to the plane of the drawing, in the same direction of movement of the frame 6.

The rising portion of the stop bar 17, which is not visible inthe drawing gradually engages the head 16 when it comes in the reach of this raised portion. When the frame 6 stops in the station A, the signal is automatically given for the unclamping operation. The flat plate 55, shifted by a jack (not shown) descends and pushes the wheels 54 of the grips 40 downwards, until the le vers 45 engage and lock in the ratchet 49, so as to lock the grips 40 in the open position and free the skin held by them.

The two operators responsible for working the ma chine according to the invention need thus to remove the skin, which is now free, from the frame which is then moved to the station B, where it recommences the cycle as described.

The invention so conceived is susceptible to numerous modifications, all of which fall within the scope of the inventive idea. Thus for example all the mentioned hydraulic jacks may be replaced by devices of electromagnetic type; all other details may equally be replaced by equivalent ones.

The materials used and dimensions may be chosen according to requirements.

I claim:

1. A machine for clamping, stretching and drying hides, comprising a drying oven having a tunnel-like interior with an inlet opening for the hides to be dried and an outlet opening for the dried hides, an outside guide rail track external to said oven and extending from a zone near said outlet opening to a zone near said inlet opening and arranged in a substantially horizonatal plane above said drying oven, a pair of internal guide rail tracks arranged within the tunnel-like interior of said drying oven comprising an internal lower guide rail track and an internal elevated guide rail track vertically at a distance from said lower guide rail track, a plurality of frame carriages for the hides to be stretched thereon and movable along said external and internal guide rail tracks, said frame carriages having at least a first and a second carriage axle at a distance from each other and defining a frame plane, said first and second carriage axles having each on each oftheir ends roller means adapted to slidably engage said guide rail tracks, the arrangement being such that when the frame carriages are on said outside guide rail track the frame planes extend parallel to the horizontal plane in which said outside guide rail track is arranged and when said frame carriages are on said pair of internal guide rail tracks the roller means of one of the axles of a frame carriage slidably engage the elevated guide rail track and the roller means of the other of said axles slidably engage the lower guide rail trach so that the said frame plane extends transverse to said horizontal plane, said frame carriages further comprising extendable plate members for the hides to be stretched thereon and clamping means for said hides, the machine further comprising transfer means for transferring said frame carriages from said outside guide rail t4ack on to said internal guide rail tracks, driving means for said transfer means and for said frame carriages and control means for said driving means.

2. A machine according to claim 1, comprising, at the opposite ends of said outside guide rail track undirectional switch points arranged one to permit the passage ofa frame carriage from said outside guide rail track to said internal guide rail tracks inside said oven, and the other to permit passage in the opposite direction.

3. A machine according to claim 1, wherein said transfer means arranged in the zone of said inlet and outlet opening comprise each a chain conveyor means extending from about the lever zone of said internal lower guide rail track to about the level zone of said outside guide rail track, dog means on said chain conveyor means and arranged releasably to grip a frame carriage and to transfer it from one among said outside guide rail track and said internal guide rail tracks to the other among said outside guide rail track and said internal guide rail tracks and automatically controllable motor means for said chain conveyor means.

.4. A machine according to claim 1, wherein said frame carriages comprise each an extendable plate structure comprising a fixed plate portion fixed on the axles of said frame carriage and :a movable plate portion slidably supported on said axles, and releasable locking means for locking said movable plate portion in a selected position on siad outside tuide rail track.

5. A machine according to claim 4, wherein said releasable locking means comprise at both axles of each of said frame carriages at least one tooth rigid with the axle, a swingable ratch member swingably pivoted on said movable plate portion and adapted to lockingly engage said tooth in selected positions of said movable plate portion, a head portion on said ratch member and releasing cam means arranged in the path of said head and adapted to release said ratch member from said tooth when said head member collides with said releasing cam means.

6. A machine according to-claim ll, further comprising jack means arranged in the zone of said outside guide rail track and laterally thereto, said jack means being adapted to move said movable plate portion away from said fixed plate portion thereby to stretch a skin fixed on said extendable plate structure, when said frame carriage is in a pre-established position on said outside guide rail track.

7. A machine according to claim 1, further comprising other jack means arranged in the zone of said outside guide rail track and laterally thereto, said other jack means being adapted to move said movable plate portion towards said fixed plate portion to relax a skin stretched on said extendable plate structure, when said frame carriage is in another pre-established position on said outside guide rail track.

8. A machine according to claim 1, further comprising grips connected to said movable and said fixed plate portions and adapted to clamp the: skin to be stretched and dryed, said grips comprising each a fixed jaw member fixable in selected positions on one among said movable and fixed plates, a movable jaw member pivoted thereon and adapted to clamp a skin portion against said fixed jaw member, lever means for opening said movable jaw member with respect to said fixed jaw member for releasing said skin portion therefrom, spring means urging said movable jaw member into its clamping position towards said fixed jaw member, ratchet means for releasably locking said lever menas in a position in which the jaws are open.

9. A machine according to claim 8, wherein said lever has a portion projecting above the remaining parts of the grip and wherein the machine further comprises a sinkable and liftable plate member adapted to engage said projecting portion of at least one grip and to press said lever into the opening position of the grip and allow thereby said ratchet means to lock the grip in its open position. 

1. A machine for clamping, stretching and drying hides, comprising a drying oven having a tunnel-like interior with an inlet opening for the hides to be dried and an outlet opening for the dried hides, an outside guide rail track external to said oven and extending from a zone near said outlet opening to a zone near said inlet opening and arranged in a substantially horizonatal plane above said drying oven, a pair of internal guide rail tracks arranged within the tunnel-like interior of said drying oven comprising an internal lower guide rail track and an internal elevated guide rail track vertically at a distance from said lower guide rail track, a plurality of frame carriages for the hides to be stretched thereon and movable along said external and inteRnal guide rail tracks, said frame carriages having at least a first and a second carriage axle at a distance from each other and defining a frame plane, said first and second carriage axles having each on each of their ends roller means adapted to slidably engage said guide rail tracks, the arrangement being such that when the frame carriages are on said outside guide rail track the frame planes extend parallel to the horizontal plane in which said outside guide rail track is arranged and when said frame carriages are on said pair of internal guide rail tracks the roller means of one of the axles of a frame carriage slidably engage the elevated guide rail track and the roller means of the other of said axles slidably engage the lower guide rail trach so that the said frame plane extends transverse to said horizontal plane, said frame carriages further comprising extendable plate members for the hides to be stretched thereon and clamping means for said hides, the machine further comprising transfer means for transferring said frame carriages from said outside guide rail track on to said internal guide rail tracks, driving means for said transfer means and for said frame carriages and control means for said driving means.
 2. A machine according to claim 1, comprising, at the opposite ends of said outside guide rail track undirectional switch points arranged one to permit the passage of a frame carriage from said outside guide rail track to said internal guide rail tracks inside said oven, and the other to permit passage in the opposite direction.
 3. A machine according to claim 1, wherein said transfer means arranged in the zone of said inlet and outlet opening comprise each a chain conveyor means extending from about the lever zone of said internal lower guide rail track to about the level zone of said outside guide rail track, dog means on said chain conveyor means and arranged releasably to grip a frame carriage and to transfer it from one among said outside guide rail track and said internal guide rail tracks to the other among said outside guide rail track and said internal guide rail tracks and automatically controllable motor means for said chain conveyor means.
 4. A machine according to claim 1, wherein said frame carriages comprise each an extendable plate structure comprising a fixed plate portion fixed on the axles of said frame carriage and a movable plate portion slidably supported on said axles, and releasable locking means for locking said movable plate portion in a selected position on siad outside guide rail track.
 5. A machine according to claim 4, wherein said releasable locking means comprise at both axles of each of said frame carriages at least one tooth rigid with the axle, a swingable ratch member swingably pivoted on said movable plate portion and adapted to lockingly engage said tooth in selected positions of said movable plate portion, a head portion on said ratch member and releasing cam means arranged in the path of said head and adapted to release said ratch member from said tooth when said head member collides with said releasing cam means.
 6. A machine according to claim 1, further comprising jack means arranged in the zone of said outside guide rail track and laterally thereto, said jack means being adapted to move said movable plate portion away from said fixed plate portion thereby to stretch a skin fixed on said extendable plate structure, when said frame carriage is in a pre-established position on said outside guide rail track.
 7. A machine according to claim 1, further comprising other jack means arranged in the zone of said outside guide rail track and laterally thereto, said other jack means being adapted to move said movable plate portion towards said fixed plate portion to relax a skin stretched on said extendable plate structure, when said frame carriage is in another pre-established position on said outside guide rail track.
 8. A machine according to claim 1, further comprising grips connected to said movable and saiD fixed plate portions and adapted to clamp the skin to be stretched and dryed, said grips comprising each a fixed jaw member fixable in selected positions on one among said movable and fixed plates, a movable jaw member pivoted thereon and adapted to clamp a skin portion against said fixed jaw member, lever means for opening said movable jaw member with respect to said fixed jaw member for releasing said skin portion therefrom, spring means urging said movable jaw member into its clamping position towards said fixed jaw member, ratchet means for releasably locking said lever menas in a position in which the jaws are open.
 9. A machine according to claim 8, wherein said lever has a portion projecting above the remaining parts of the grip and wherein the machine further comprises a sinkable and liftable plate member adapted to engage said projecting portion of at least one grip and to press said lever into the opening position of the grip and allow thereby said ratchet means to lock the grip in its open position. 